Trolling motor - MinnKota Riptide Repair Thread

Hello I'm starting this thread a tad early so I can start gathering info and get help knowing where to look.

Recently I ran into a fisherman that got sold 3 bum trolling motor's their really good motors and sell for $500-$1500. They are saltwater specific Minn Kota Riptide motors. 55lb, 55lb, and a 40lb. The 2 we need to fix are the 55lb thrust ones. The problem is there is no throttle control. Its either on full blast or off. He had it repaired by someone and they didn't close it up and left it unsealed so he could go in and repair the 2nd one himself and use the 1st as reference. Needless to say he's now left with 2 non working motors. Originally the 1 he had repaired worked so hopefully we won't need parts on one of them. If anyone has any repair manuals for a trolling motor or schematics of one please post them. I don't think brand really matters that much but something for reference would be good. I plan on going over there on Sat or Sun and will post pictures as were working on it. I know this seems to be a very common problem and hopeing we can get it running so we can start buying them broken and repairing them. So far I'm thinking its probably an ungrounded or broken variable resistor but who knows. It may have seperate resistors for each speed setting. Think about it if you can or if you have other ideas for me to check please let me know so I can get right to work when I get to his house. For tools I have a great iron, multimeter, and most common resistors and caps.
Thanks and I'll keep you posted.

I'd be surprised if it's such a simple control as a variable resistor -- that would be an inefficient design, especially since it has to run on a battery. I'd imagine something more suitable like an H-bridge would be used. (I think my brother once told me that's what's used on his trolling motor.)

Did you call the company number Wookie pointed to to see if they'll send you a schematic and parts list? That's always the first thing to try.

Yes we contacted the company and the best they could do was to send us another controller board, or send it to them and have them replace the controller board. I think it was $150 for the board or $200 to have them install it.

original style used a switch with a number of resistance wires down to the +ve brush ..later used a ~PWM controller which you can duplicate ...dont run it out of water you will bugger the seal on the shaft !! They run good on 24v